This invention is directed toward the solution of two problems associated with the use and operation of pressurized air hoses. The first of these problems is excessive or uncontrolled air flow, resulting in a whipping action of the hose, when an air hose ruptures or is severed or is connected to an air source before the downstream end is connected to the device intended to be powered by the pressurized air. The second problem is the rapid spontaneous exhaust of air from the hose in the direction opposite to the direction of normal flow when the hose is being disconnected from a source of pressurized air. Both conditions are problems because the resultant motion of the hose can cause injury or damage to nearby persons and equipment.
There have been various attempts to solve the hose whipping problem by the use of pneumatic velocity valves. These attempts have been only marginally effective. Commercially available pneumatic velocity valves are generally large in size in relation to their function and are usually quite costly. In addition, since they must be plumbed directly into each coupling of a coupling bulkhead (a piping fixture that usually contains one or more female quick disconnect air hose couplings) and since each valve must be preset for use with a specific type of air hose coupling and air hose, the commercially available valves lack versatility. A given valve can only be used with the size air hose for which it is preset if the valve is to function properly. A valve that is set for a larger air hose, such as a three-quarter inch hose, will not function to cut off excessive flow through a smaller air hose, such as a one-half inch hose. The smaller hose cannot pass a large enough volume of air to actuate the flow check mechanism even though the volume of air passed is large enough to make the hose whip violently.
The commercially available pneumatic velocity valves may also be ineffective in preventing hose whipping when two or more hoses are connected in series. Such an arrangement of hoses limits the amount of air that can be passed by the connected hoses, and therefore, should the flow become excessive, there might not be a sufficient volume of air to actuate the flow check mechanism of the valve that is plumbed into the coupling.
Conventional methods for dealing with the problem of the rapid spontaneous exhaust of pressurized air when the hose is disconnected have also been only marginally effective. The common solution to the problem has been to use a "zero-pressure" quick disconnect air hose coupling. Such a coupling vents the pressurized air from the air hose before the hose can be removed from the coupling. In comparison to non-zero-pressure quick disconnect couplings, the zero-pressure quick disconnect couplings are generally larger, more costly, and more complicated to operate. In addition, they restrict the flow of air through the coupling during normal flow conditions more than non-zero-pressure quick disconnect couplings.
The following U.S. patents disclose valves for use in fluid lines:
U.S. Pat. No. 701,754, granted June 3, 1902, to T. W. Moran; PA1 U.S. Pat. No. 1,466,171, granted Aug. 28, 1923, to O. Jacobsen; PA1 U.S. Pat. No. 2,454,480, granted Nov. 23, 1948, to D. Rossman; PA1 U.S. Pat. No. 2,623,725, granted Dec. 30, 1952, to A. D. Sands; PA1 U.S. Pat. No. 2,889,850, granted June 9, 1959, to W. C. Eberline; PA1 U.S. Pat. No. 3,017,871, granted Jan. 23, 1962, to J. T. McKiney; PA1 U.S. Pat. No. 3,085,589, granted Apr. 16, 1963, to A. D. Sands; PA1 U.S. Pat. No. 3,122,162, granted Feb. 25, 1964, to A. D. Sands; PA1 U.S. Pat. No. 3,326,233, granted June 20, 1967, to J. E. Perruzzi; PA1 U.S. Pat. No. 4,104,004, granted Aug. 1, 1978, to M. L. Graef; and PA1 U.S. Pat. No. 4,120,316, granted Oct. 17, 1978, to G. P. Robinson, Jr. et al.
For the most part, these patents are only of general interest and do not disclose valves that are closely related in function or structure to the two-way fuse of the present invention. However, three of the patents are more specifically related and will be discussed separately.
Sands U.S. Pat. No. 2,623,725 and Sands U.S. Pat. No. 3,085,589 each disclose a valve that has a main function of checking flow in the forward direction in the event of hose breakage. The first of these valves, U.S. Pat. No. 2,623,725, is designed to work in either one of two directions, but only in the forward flow direction. In order to have the valve operate in the opposite direction, the valve is turned around in the system, resulting in a different operating sensitivity. The second of these valves, U.S. Pat. No. 3,085,589, is disclosed to operate in the reverse, as well as the forward, direction. However, the valve is only described as operating in the reverse direction when there is excessive flow in the reverse direction; there is no discussion of the valve functioning when the hose is being disconnected. Both of the patents disclose a valve with a valve member that is balanced in a center position by two oppositely directed springs. Thus, any amount of flow in either direction will cause the valve member to move away from its center position and thereby cause some degree of restriction in the flow in that direction.
Perruzzi U.S. Pat. No. 3,326,233 discloses a valve that checks excessive flow in the forward direction and that closes off the flow path when there is flow in the reverse direction. The structure and functioning of the valve is based on the principal of the Venturi tube, and the valve is designed principally to operate in a vertical position.
The above patents and the prior art that is discussed and/or cited therein should be studied for the purpose of putting the present invention into proper perspective relative to the prior art.